1. Field of the Invention
An instrument panel structure for a vehicle is provided. The panel structure includes an energy absorbing panel member fabricated of a relatively rigid impact resistant resinous material modified so that one portion gives more readily under impact than do other portions.
2. Prior Art
Increasing attention has been paid in recent years to the provision of instrument panels for automotive vehicles which will tend to reduce injury to vehicle occupants as a consequence of impact with the instrument panel on the occurrence of sudden decelerations caused by accidents or rapid braking action.
Instrument panels are subject to two different types of vehicle occupant impact. One type of impact involves doubling over of the occupant whereupon his head will impact the instrument panel. Head injuries are, of course, very serious and it is desired to provide an instrument panel which, when impacted by an occupant's head, will give and absorb energy of impact in a manner to ease impact forces.
The other type of impact is with the vehicle occupant's knees against the lower portion of the instrument panel. While it is, of course, desirable to protect the knees from injury, there is another problem associated with such impact. The lower portion of the body is heavier than the upper portion. When the knee contacts the instrument panel it means that the lower portion of the body is moving forwardly. It is desired to prevent such forward movement within the constraints of minimizing knee injury in order to protect the vehicle occupant from more severe injury which may be caused by such forward movement of the lower body portion. Therefore, the lower portion of the instrument panel should not give as much as the upper portion.
The difference in the two types of impacts has resulted in an instrument panel designed problem. If the panel is constructed so as to give under lower impact forces so as to protect the head, it will also give under relatively low knee impact forces which is undesirable. The reverse proposition is true, that is, if the instrument panel is made more rigid so as to not give under knee impact forces, it will not give sufficiently under head impact forces.
One solution to this problem which has been proposed is to weaken the joint interconnecting the upper and lower portions of the instrument panel so that the instrument panel will, in effect, bend under head impact forces. A reinforcing element may then be provided on the lower instrument panel portion to prevent movement of the lower portion. The various ways this might be done present manufacturing problems which have been difficult to overcome.
In accordance with the present invention, the lower portion of the instrument panel is made sufficiently strong so as to properly resist knee impact forces. The upper portion of the panel is embossed on the reverse side to result in a plurality of protuberances which are spaced apart from each other. This has weakened the upper portion of the panel sufficiently to permit it to give under the head impact forces in a desired manner. The result is a one-piece instrument panel structure which serves both the needs of energy absorbing for head impact and energy absorbing for knee impact.